Cable crane



Patented Mar. 24, 1936 UNITED STATES PATENT OFFICE CABLE CRANE Giinther Voss, Stuttgart, Germany Application September 28, 1931, Serial'No. 565;619

5 Claims.

Theipresent invention relates'to a rope or cable crane, the object of the invention beingto provide an improvedapparatus of this kind inwhich the load-carrying rope also serves as lifting ropes and in which the weight of the pulley block is taken up by means ofa special rope which is suspended betweenthe pulleys mounted on. the supporting-pillars or brackets, saidirope stretched at a constant tension, orthe carrying rope has an additional pulll or tension imparted to it by means of a counterweight which is designed to neutralize the weight of the pulley block;

With theabove and otherobjects-in view, the invention consists in'the construction, combinationand arrangement of devices hereinafter described and claimed.

In the accompanying drawing Figure l is a diagrammaticelevation ofl a cable crane-constructedland arranged in accordance with; myinvention;

Figure 2 is a similar view of a modified form of the cable crane.

Figure 3 is-a-detail'diagrammatic elevation of the supportingrevoluble drum 24 andia portion of' the cable and" of the counterweight and the ropes sustaining said counterweight from said drum.

Figure 4' is a detairplanof the same;

Fig. 1 inthe appended drawing shows an embodiment' of the present invention. The carrying rope ortravelling cable 2' which is fixed-to the block I at one of its extremities as at l is carried overthe driving-pulley 4' mounted on the support3, then' extends downwardly and passes over the loose pulley 5, then upwardly and over the pulley 6 of the support 3, and over the'guide pulley lof'the block I and is then carried over the rope pulley-tof-thesupport 9 and back over to-the-pulley lflof-the-block l. The depending -encl'ofthecarryingrope-carries the load H. The rope I2 is carried from the loose roller or pulley 5 to the rope drum l3 ofthe winch. If the driving pulley 4' is prevented fromrotating, then assumingtheproper frictional adhesion between the load carrying rope and the driving pulley 4 to exist-thelengthof' the load carrying rope between the said driving pulley 4 and the block I remains stationary, the latter can therefore not move in a horizontal direction.

If however the loose roller 5 is pulled downwardly by means of the haulage drum l3, the load H is pulled upwardly over the rollers or pulleys l0, 8, I, 6, and 5 by means of the portion of the carrying rope running over said rollers; and if the loose pulley is raised the load is lowered. If the level of the loose pulley 5 is fixed by means of locking the haulagedrum, then the block I is pulled when the driving pulley 4- rotates left-handedly by the length of the carrying rope between pulley 4 and the' pulley block to *5 the left and when the pulley 4 rotates righthandedly'the pulley'block moves to the right.

The weight" of the rope block I: istaken up by the relievingrope I8 which is fixed at M to the support'3 and runsunder the pulley l5 of the 10 block I andLoVer the pulley l6 mounted at the upper end of the lateral support 9. Saidropei I8 is kept at a constant tension by means of the counterweight IT toiwhich its free depending end is attached;

Toillustrate the operation of the invention, the following is: in point: If the weight of the load is'de'signated with P; the pull'in the supporting cable 2 equalstalso P. Asthe rolls l0, 8, and I are freely rotatablein each of the four supporting cable strands, arranged laterally on the crane trolley, also the: pull P must be present, if the crane trolley is: in the center between both the lateral supports; When. a designates the angle of the supporting cable strands, extending laterally fromthe. trolley against the horizontal, the equilibrium condition at the'cran'e trolley reads, when thedea'dweight thereof .is balanced by the cable l8: P=4Pi sin a; from this results:- sin a=%. This equationshows that the angle a and therewith also the sag of the supporting cable is independent of the. positionof height of the load; Hence the'sag of the supporting cable is constant during the lifting. of the load;

Fig. 2 shows another embodiment; Figs. 3 and 4 show the devices adopted to producea constant and additional pull'or tension onthe carrying rope, for'the purpose of neutralizing the weight of the pulley block, on an enlarged scale bothin elevation and plan view. In this case the' load carrying rope l9 consists of two ropes hanging down from-the rope pulley block which together take up the loads, the load carrying rope cohsisting in the horizontal direction of four ropes. Said load carrying rope is carried from the lifting drum:2'0I fixed tothe lateral =support -9-, over the rope pulleys 2| to 23 forming a depending bight therebetween and passes then on to the tension drum 24, being coiled several times around it, so as to create the required frictional adhesion. From said drum the rope runs over the rope pulleys 25 to 21 to the driving pulley 28 and from there over the rope pulley 29 of the pulley block to the point 30 where it is fixed to the lateral support 9. It is possible to divide the carrying rope on the drum 24 and the two rope extremities produced by this division can be fixed to the drum. There is further another rope 3|, fixed to this drum, which is subjected to a constant tension by reason of the counterweight 32.

By means of, this rope the three top strands of the load carrying rope l9 have an additional pull imparted to them which is utilized to neutralize the weight of the pulley block.

By reason of this arrangement the rather awkwardly long rope l8 of the first embodiment is eliminated, moreover the sagging of the upper ropes or rope strands when the crane is not loaded is very considerably reduced so that the dead or idle lift is also considerably reduced.

If the driving pulley 28 is locked and prevented from rotating, then the lengths of the carrying rope between the rope pulley 29 and the driving pulley 28 and the fixing point 30 remain stationary, i. e., the pulley block can not be displaced laterally; the load is then raised or lowered in the manner known per se by rotating the lifting drum 2!). If the latter, however, is locked then the lengths of the carrying rope between the rope pulley 29 and the driving pulley 28 or the point of fixation 30 are, by reason of rotating said driving pulley 28, lengthened or shortened, so that the pulley block and the load moves to the right or left according to the direction of rotation of the driving pulley.

I claim:

1. A cable crane comprising supporting elements arranged at spaced points, a cable having bights slidably engaging said supports so that the cable is suspended by and between said supports, a pulley block carried by and also movable on and by the cable, load attaching means on a portion of the cable extending downwardly from said pulley block, means for balancing the weight of the pulley block and the cable, means to apply tension to the cable for shortening the effective length of the same and thereby raise the load attaching means while maintaining constant the sag of the cable, and a driving drum around which the cable passes for causing the load attaching means to be hauled by the cable.

2. A cable crane comprising supporting elements arranged at spaced points, a cable supported by, movable on and suspended in depending bights between said supporting elements and constituting in itself, both a lifting cable and a carrying cable, a pulley block' carried by and also movable on and by said cable, load attaching means on a portion of the cable extending downwardly from said pulley block, means for balancing the weight of said pulley block and the cable, means for shortening the effective length of the cable to raise the load attaching means while maintaining constant the sag of the cable, and a driving drum around which the cable passes for causing the pulley block and therewith the load attaching means to be conveyed toward either one of said supporting elements.

3. A cable crane comprising supporting elements arranged at spaced points, a cable supported by, movable on and suspended in depending bights between said supporting elements and constituting in itself both a lifting cable and a carrying cable, a pulley block carried by and also movable on and by said cable, load attaching means on a portion of the cable extending downwardly from said pulley block, means for balancing the weight of said pulley block and the cable, means for shortening the effective length of cable to raise the load attaching means while maintaining constant the sag of the cable, said means comprising a lifting drum to which one end of said cable is secured and adapted to be wound thereon, the other end of said cable being anchored to a stationary element, and a driving drum around which the cable passes for causing the pulley block and therewith the load attaching means to be conveyed toward either one of said supporting elements.

4. A. cable crane comprising supporting elements arranged'at spaced points, a cable supported by, movable on and suspended in depending bights between said supporting elements and constituting in itself both a lifting cable and a carrying cable, a pulley block carried by and also movable on and by said cable, load attaching means on a portion of the cable extending downwardly from said pulley block, means for balancing the weight of said pulley block and the cable, means for shortening the effective length of cable to raise the load attaching means while maintaining constant the sag of the cable, said means comprising a vertically movable pulley arranged in a downwardly extending bight of said cable and adapted to vary the length of said bight, and a driving drum around which the cable passes for causing the pulley block and therewiththe load attaching means to be conveyed toward either one of said supporting ele- 'ments.

5. A cable crane comprising, supporting elements arranged at spaced points, a cable supported by, movable on and suspended in depending bights between said supporting elements and constituting in itself both a lifting cable and a carrying cable, a pulley block carried by and also movable on and by said cable, load attaching means on a portion of the cable extending downwardly from said pulley block, means for balancing the weight of said pulley block and the cable, said balancing means comprising a rope which is secured with one of its ends to one of said supporting elements, passes slidably through said pulley block and is slidably supported by said other supporting element, and a counter weight attached to the other end of said rope; means for shortening the effective length of cable to raise the load attaching means while maintaining constant the sag of the cable, and a driving drum around which the cable passes for causing the pulley block and therewith the load attaching means to be conveyed toward either one of said supporting elements.

GfiNTI-IER voss. 

